The present invention is related to a liquid crystal display with a Fresnel lens reflective layer, in which the resin layer has a Fresnel lens with concentric annular structures such that the reflective layer is laid on the resin layer for both reflecting and scattering the light.
In a conventional reflective liquid crystal display, the external light is reflected by the reflective film of the liquid crystal display to provide necessary light source for the display. Therefore, the reflective liquid crystal display has no in-built light source so that the thickness is reduced and the power is saved. However, the quality of the image of such reflective liquid crystal display is determined by the distribution of the reflected light. According to reflection principle (as shown in FIG. 8), the angle a contained by the incident light 81 and the normal line 82 is equal to the angle b contained by the reflected light 83 and the normal line 82. Therefore, in the case of large angle of incidence, the angle of reflection will be also large. Under such circumstance, a user 84 perpendicular to the liquid crystal display can hardly see the reflected light. As a result, the brightness and comparability of such liquid crystal display are poor.
The reflective film of the conventional reflective liquid crystal display mostly employs symmetrical and periodical reflective units. However, the symmetrical reflective units cannot conduct the reflected light by a necessary angle. Also, the arrangement of the periodical reflective units will lead to problems of interference and stripes of chromatic aberration.
Referring to FIG. 9, when such reflective liquid crystal display is turned to a position with brighter light source, the light 85 reflected by the surface 80 of the display will coincide with the light 87 reflected by the reflective film 86. This will lead to glare and reduce comparability of the image.
In order to solve the above problems, an improved reflective liquid crystal display has been developed as shown in FIG. 10. In such display, a scattering layer 92 is overlaid on the upper transparent substrate 91. The scattering layer 92 includes numerous asymmetrical protuberances 921 having concentric stripes for changing the path of the incident light 93 and providing anti-glare function. However, in such reflective liquid crystal display, the scattering layer 92 is farther from the reflective layer 94 so that the problem of chromatic aberration will take place.
FIG. 11 is a cross-sectional view of another type of conventional reflective liquid crystal display, in which the lower transparent substrate 95 includes numerous sloped protuberances 96 for providing anti-glare function. In addition, each sloped protuberance 96 has multiple scattering projections 961 for scattering the light. However, such sloped protuberances 96 with scattering projections 961 necessitate two times of yellow light manufacturing procedures. This increases the cost and lowers the ratio of good products.
It is therefore a primary object of the present invention to provide a liquid crystal display with a Fresnel lens reflective layer. In the liquid crystal display, the resin layer is composed of numerous units arranged respectively corresponding to the pixels of the display. Each unit has multiple regions. Each region has a part of the concentric annular structure with a Fresnel lens pattern. The structure with a Fresnel lens pattern has asymmetrical and non-periodical structural pattern. The reflective layer is plated on the resin layer and has the same structural pattern. When the light is reflected by the reflective layer of such structure, the light is scattered and the path of the light is changed to provide anti-glare function. Moreover, in the case of large angle of incidence, the reflective layer can evenly scatter the light to achieve better brightness and comparability than the prior art. Also, the asymmetrical and non-periodical structural pattern can enhance the brightness and avoid the interference.
It is a further object of the present invention to provide the above liquid crystal display with a Fresnel lens reflective layer in which the reflective layer can both reflect and scatter the light so that the problem of chromatic aberration is solved. The liquid crystal display is made by one time of yellow light manufacturing procedure so that the cost is lowered.
According to the above objects, the liquid crystal display with a Fresnel lens reflective layer of the present invention includes an upper transparent substrate, a lower transparent substrate and a liquid crystal layer sandwiched between the upper and lower transparent substrates. One face of the liquid crystal layer adjacent to the upper transparent substrate has an upper transparent electrode, while the other face of the liquid crystal layer adjacent to the lower transparent substrate has a lower transparent electrode. Between the lower transparent substrate and the lower transparent electrode are sequentially piled a dielectric layer, a resin layer, a reflective layer and an insulating layer. The resin layer is composed of numerous units each having at least one region. The region has a part of the Fresnel lens concentric annular structure. The reflective layer is laid on the resin layer. The surface of the reflective layer has the Fresnel lens concentric annular structures for reflecting and scattering the light.
The present invention can be best understood through the following description and accompanying drawings wherein: